/*
   Copyright 2020 The Compose Specification Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package paths

import (
	"errors"
	"fmt"
	"path/filepath"

	"github.com/compose-spec/compose-go/v2/tree"
	"github.com/compose-spec/compose-go/v2/types"
)

type resolver func(any) (any, error)

// ResolveRelativePaths make relative paths absolute
func ResolveRelativePaths(project map[string]any, base string, remotes []RemoteResource) error {
	r := relativePathsResolver{
		workingDir: base,
		remotes:    remotes,
	}
	r.resolvers = map[tree.Path]resolver{
		"services.*.build.context":               r.absContextPath,
		"services.*.build.additional_contexts.*": r.absContextPath,
		"services.*.env_file.*.path":             r.absPath,
		"services.*.extends.file":                r.absExtendsPath,
		"services.*.develop.watch.*.path":        r.absSymbolicLink,
		"services.*.volumes.*":                   r.absVolumeMount,
		"configs.*.file":                         r.maybeUnixPath,
		"secrets.*.file":                         r.maybeUnixPath,
		"include.path":                           r.absPath,
		"include.project_directory":              r.absPath,
		"include.env_file":                       r.absPath,
		"volumes.*":                              r.volumeDriverOpts,
	}
	_, err := r.resolveRelativePaths(project, tree.NewPath())
	return err
}

type RemoteResource func(path string) bool

type relativePathsResolver struct {
	workingDir string
	remotes    []RemoteResource
	resolvers  map[tree.Path]resolver
}

func (r *relativePathsResolver) isRemoteResource(path string) bool {
	for _, remote := range r.remotes {
		if remote(path) {
			return true
		}
	}
	return false
}

func (r *relativePathsResolver) resolveRelativePaths(value any, p tree.Path) (any, error) {
	for pattern, resolver := range r.resolvers {
		if p.Matches(pattern) {
			return resolver(value)
		}
	}
	switch v := value.(type) {
	case map[string]any:
		for k, e := range v {
			resolved, err := r.resolveRelativePaths(e, p.Next(k))
			if err != nil {
				return nil, err
			}
			v[k] = resolved
		}
	case []any:
		for i, e := range v {
			resolved, err := r.resolveRelativePaths(e, p.Next("[]"))
			if err != nil {
				return nil, err
			}
			v[i] = resolved
		}
	}
	return value, nil
}

func (r *relativePathsResolver) absPath(value any) (any, error) {
	switch v := value.(type) {
	case []any:
		for i, s := range v {
			abs, err := r.absPath(s)
			if err != nil {
				return nil, err
			}
			v[i] = abs
		}
		return v, nil
	case string:
		v = ExpandUser(v)
		if filepath.IsAbs(v) {
			return v, nil
		}
		if v != "" {
			return filepath.Join(r.workingDir, v), nil
		}
		return v, nil
	}

	return nil, fmt.Errorf("unexpected type %T", value)
}

func (r *relativePathsResolver) absVolumeMount(a any) (any, error) {
	switch vol := a.(type) {
	case map[string]any:
		if vol["type"] != types.VolumeTypeBind {
			return vol, nil
		}
		src, ok := vol["source"]
		if !ok {
			return nil, errors.New(`invalid mount config for type "bind": field Source must not be empty`)
		}
		abs, err := r.maybeUnixPath(src.(string))
		if err != nil {
			return nil, err
		}
		vol["source"] = abs
		return vol, nil
	default:
		// not using canonical format, skip
		return a, nil
	}
}

func (r *relativePathsResolver) volumeDriverOpts(a any) (any, error) {
	if a == nil {
		return nil, nil
	}
	vol := a.(map[string]any)
	if vol["driver"] != "local" {
		return vol, nil
	}
	do, ok := vol["driver_opts"]
	if !ok {
		return vol, nil
	}
	opts := do.(map[string]any)
	if dev, ok := opts["device"]; opts["o"] == "bind" && ok {
		// This is actually a bind mount
		path, err := r.maybeUnixPath(dev)
		if err != nil {
			return nil, err
		}
		opts["device"] = path
	}
	return vol, nil
}